title: Maternal control of PIN1 is required for female gametophyte development in Arabidopsis.
abstract: Land plants are characterised by haplo-diploid life cycles, and developing ovules are the organs in which the haploid and diploid generations coexist. Recently it has been shown that hormones such as auxin and cytokinins play important roles in ovule development and patterning. The establishment and regulation of auxin levels in cells is predominantly determined by the activity of the auxin efflux carrier proteins PIN-FORMED (PIN). To study the roles of PIN1 and PIN3 during ovule development we have used mutant alleles of both genes and also perturbed PIN1 and PIN3 expression using micro-RNAs controlled by the ovule specific DEFH9 (DEFIFICENS Homologue 9) promoter. PIN1 down-regulation and pin1-5 mutation severely affect female gametophyte development since embryo sacs arrest at the mono- and/or bi-nuclear stages (FG1 and FG3 stage). PIN3 function is not required for ovule development in wild-type or PIN1-silenced plants. We show that sporophytically expressed PIN1 is required for megagametogenesis, suggesting that sporophytic auxin flux might control the early stages of female gametophyte development, although auxin response is not visible in developing embryo sacs.
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Ceccato
authors.forename: Simona
authors.initials: S
authors.lastname: Masiero
authors.forename: Dola
authors.initials: D
authors.lastname: Sinha Roy
authors.forename: Stefano
authors.initials: S
authors.lastname: Bencivenga
authors.forename: Irma
authors.initials: I
authors.lastname: Roig-Villanova
authors.forename: Franck Anicet
authors.initials: FA
authors.lastname: Ditengou
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Simon
authors.forename: Lucia
authors.initials: L
authors.lastname: Colombo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026901:Membrane Transport Proteins / Q000235:genetics / Q000502:physiology*; D056771:Ovule
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis